<?php
/**
 * CHtmlPurifier class file.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @link http://www.yiiframework.com/
 * @copyright 2008-2013 Yii Software LLC
 * @license http://www.yiiframework.com/license/
 */

if (!class_exists('HTMLPurifier_Bootstrap', false)) {
    require_once(Yii::getPathOfAlias('system.vendors.htmlpurifier') . DIRECTORY_SEPARATOR . 'HTMLPurifier.standalone.php');
    HTMLPurifier_Bootstrap::registerAutoload();
}

/**
 * CHtmlPurifier is wrapper of {@link http://htmlpurifier.org HTML Purifier}.
 *
 * CHtmlPurifier removes all malicious code (better known as XSS) with a thoroughly audited,
 * secure yet permissive whitelist. It will also make sure the resulting code
 * is standard-compliant.
 *
 * CHtmlPurifier can be used as either a widget or a controller filter.
 *
 * Note: since HTML Purifier is a big package, its performance is not very good.
 * You should consider either caching the purification result or purifying the user input
 * before saving to database.
 *
 * Usage as a class:
 * <pre>
 * $p = new CHtmlPurifier();
 * $p->options = array('URI.AllowedSchemes'=>array(
 *   'http' => true,
 *   'https' => true,
 * ));
 * $text = $p->purify($text);
 * </pre>
 *
 * Usage as validation rule:
 * <pre>
 * array('text','filter','filter'=>array($obj=new CHtmlPurifier(),'purify')),
 * </pre>
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @package system.web.widgets
 * @since 1.0
 */
class CHtmlPurifier extends COutputProcessor
{
    /**
     * @var object the HTML Purifier instance.
     */
    private $_purifier;
    /**
     * @var mixed the options to be passed to HTML Purifier instance.
     * This can be a HTMLPurifier_Config object,  an array of directives (Namespace.Directive => Value)
     * or the filename of an ini file.
     * @see http://htmlpurifier.org/live/configdoc/plain.html
     */
    private $_options = null;

    /**
     * Processes the captured output.
     * This method purifies the output using {@link http://htmlpurifier.org HTML Purifier}.
     * @param string $output the captured output to be processed
     */
    public function processOutput($output)
    {
        $output = $this->purify($output);
        parent::processOutput($output);
    }

    /**
     * Purifies the HTML content by removing malicious code.
     * @param mixed $content the content to be purified.
     * @return mixed the purified content
     */
    public function purify($content)
    {
        if (is_array($content))
            $content = array_map(array($this, 'purify'), $content);
        else
            $content = $this->getPurifier()->purify($content);
        return $content;
    }

    /**
     * Set the options for HTML Purifier and create a new HTML Purifier instance based on these options.
     * @param mixed $options the options for HTML Purifier
     * @return CHtmlPurifier
     */
    public function setOptions($options)
    {
        $this->_options = $options;
        $this->createNewHtmlPurifierInstance();
        return $this;
    }

    /**
     * Get the options for the HTML Purifier instance.
     * @return mixed the HTML Purifier instance options
     */
    public function getOptions()
    {
        return $this->_options;
    }

    /**
     * Get the HTML Purifier instance or create a new one if it doesn't exist.
     * @return HTMLPurifier
     */
    protected function getPurifier()
    {
        if ($this->_purifier !== null)
            return $this->_purifier;
        return $this->createNewHtmlPurifierInstance();
    }

    /**
     * Create a new HTML Purifier instance.
     * @return HTMLPurifier
     */
    protected function createNewHtmlPurifierInstance()
    {
        $this->_purifier = new HTMLPurifier($this->getOptions());
        $this->_purifier->config->set('Cache.SerializerPath', Yii::app()->getRuntimePath());
        return $this->_purifier;
    }
}
